Re-write mono module editor code in C#

Make the build system automatically build the C# Api assemblies to be shipped with the editor.
Make the editor, editor player and debug export templates use Api assemblies built with debug symbols.
Always run MSBuild to build the editor tools and Api assemblies when building Godot.
Several bugs fixed related to assembly hot reloading and restoring state.
Fix StringExtensions internal calls not being registered correctly, resulting in MissingMethodException.

10 files changed, 841 insertions, 0 deletions

diff --git a/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/ApiAssembliesInfo.cs b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/ApiAssembliesInfo.cs
new file mode 100644
index 0000000000..345a472185
--- /dev/null
+++ b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/ApiAssembliesInfo.cs
@@ -0,0 +1,15 @@
+namespace GodotTools
+{
+    public static class ApiAssemblyNames
+    {
+        public const string SolutionName = "GodotSharp";
+        public const string Core = "GodotSharp";
+        public const string Editor = "GodotSharpEditor";
+    }
+
+    public enum ApiAssemblyType
+    {
+        Core,
+        Editor
+    }
+}
diff --git a/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/ApiSolutionGenerator.cs b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/ApiSolutionGenerator.cs
new file mode 100644
index 0000000000..bfae2afc13
--- /dev/null
+++ b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/ApiSolutionGenerator.cs
@@ -0,0 +1,52 @@
+using System.Collections.Generic;
+using System.IO;
+
+namespace GodotTools.ProjectEditor
+{
+    public static class ApiSolutionGenerator
+    {
+        public static void GenerateApiSolution(string solutionDir,
+            string coreProjDir, IEnumerable<string> coreCompileItems,
+            string editorProjDir, IEnumerable<string> editorCompileItems)
+        {
+            var solution = new DotNetSolution(ApiAssemblyNames.SolutionName);
+
+            solution.DirectoryPath = solutionDir;
+
+            // GodotSharp project
+
+            const string coreApiAssemblyName = ApiAssemblyNames.Core;
+
+            string coreGuid = ProjectGenerator.GenCoreApiProject(coreProjDir, coreCompileItems);
+
+            var coreProjInfo = new DotNetSolution.ProjectInfo
+            {
+                Guid = coreGuid,
+                PathRelativeToSolution = Path.Combine(coreApiAssemblyName, $"{coreApiAssemblyName}.csproj")
+            };
+            coreProjInfo.Configs.Add("Debug");
+            coreProjInfo.Configs.Add("Release");
+
+            solution.AddNewProject(coreApiAssemblyName, coreProjInfo);
+
+            // GodotSharpEditor project
+
+            const string editorApiAssemblyName = ApiAssemblyNames.Editor;
+
+            string editorGuid = ProjectGenerator.GenEditorApiProject(editorProjDir,
+                $"../{coreApiAssemblyName}/{coreApiAssemblyName}.csproj", editorCompileItems);
+
+            var editorProjInfo = new DotNetSolution.ProjectInfo();
+            editorProjInfo.Guid = editorGuid;
+            editorProjInfo.PathRelativeToSolution = Path.Combine(editorApiAssemblyName, $"{editorApiAssemblyName}.csproj");
+            editorProjInfo.Configs.Add("Debug");
+            editorProjInfo.Configs.Add("Release");
+
+            solution.AddNewProject(editorApiAssemblyName, editorProjInfo);
+
+            // Save solution
+
+            solution.Save();
+        }
+    }
+}
diff --git a/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/DotNetSolution.cs b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/DotNetSolution.cs
new file mode 100644
index 0000000000..76cb249acf
--- /dev/null
+++ b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/DotNetSolution.cs
@@ -0,0 +1,122 @@
+using GodotTools.Core;
+using System.Collections.Generic;
+using System.IO;
+
+namespace GodotTools.ProjectEditor
+{
+    public class DotNetSolution
+    {
+        private string directoryPath;
+        private readonly Dictionary<string, ProjectInfo> projects = new Dictionary<string, ProjectInfo>();
+
+        public string Name { get; }
+
+        public string DirectoryPath
+        {
+            get => directoryPath;
+            set => directoryPath = value.IsAbsolutePath() ? value : Path.GetFullPath(value);
+        }
+
+        public class ProjectInfo
+        {
+            public string Guid;
+            public string PathRelativeToSolution;
+            public List<string> Configs = new List<string>();
+        }
+
+        public void AddNewProject(string name, ProjectInfo projectInfo)
+        {
+            projects[name] = projectInfo;
+        }
+
+        public bool HasProject(string name)
+        {
+            return projects.ContainsKey(name);
+        }
+
+        public ProjectInfo GetProjectInfo(string name)
+        {
+            return projects[name];
+        }
+
+        public bool RemoveProject(string name)
+        {
+            return projects.Remove(name);
+        }
+
+        public void Save()
+        {
+            if (!Directory.Exists(DirectoryPath))
+                throw new FileNotFoundException("The solution directory does not exist.");
+
+            string projectsDecl = string.Empty;
+            string slnPlatformsCfg = string.Empty;
+            string projPlatformsCfg = string.Empty;
+
+            bool isFirstProject = true;
+
+            foreach (var pair in projects)
+            {
+                string name = pair.Key;
+                ProjectInfo projectInfo = pair.Value;
+
+                if (!isFirstProject)
+                    projectsDecl += "\n";
+
+                projectsDecl += string.Format(ProjectDeclaration,
+                    name, projectInfo.PathRelativeToSolution.Replace("/", "\\"), projectInfo.Guid);
+
+                for (int i = 0; i < projectInfo.Configs.Count; i++)
+                {
+                    string config = projectInfo.Configs[i];
+
+                    if (i != 0 || !isFirstProject)
+                    {
+                        slnPlatformsCfg += "\n";
+                        projPlatformsCfg += "\n";
+                    }
+
+                    slnPlatformsCfg += string.Format(SolutionPlatformsConfig, config);
+                    projPlatformsCfg += string.Format(ProjectPlatformsConfig, projectInfo.Guid, config);
+                }
+
+                isFirstProject = false;
+            }
+
+            string solutionPath = Path.Combine(DirectoryPath, Name + ".sln");
+            string content = string.Format(SolutionTemplate, projectsDecl, slnPlatformsCfg, projPlatformsCfg);
+
+            File.WriteAllText(solutionPath, content);
+        }
+
+        public DotNetSolution(string name)
+        {
+            Name = name;
+        }
+
+        const string SolutionTemplate =
+@"Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio 2012
+{0}
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+{1}
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+{2}
+	EndGlobalSection
+EndGlobal
+";
+
+        const string ProjectDeclaration =
+@"Project(""{{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}}"") = ""{0}"", ""{1}"", ""{{{2}}}""
+EndProject";
+
+        const string SolutionPlatformsConfig =
+@"	{0}|Any CPU = {0}|Any CPU";
+
+        const string ProjectPlatformsConfig =
+@"		{{{0}}}.{1}|Any CPU.ActiveCfg = {1}|Any CPU
+		{{{0}}}.{1}|Any CPU.Build.0 = {1}|Any CPU";
+    }
+}
diff --git a/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/GodotTools.ProjectEditor.csproj b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/GodotTools.ProjectEditor.csproj
new file mode 100644
index 0000000000..08b8ba3946
--- /dev/null
+++ b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/GodotTools.ProjectEditor.csproj
@@ -0,0 +1,64 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectGuid>{A8CDAD94-C6D4-4B19-A7E7-76C53CC92984}</ProjectGuid>
+    <OutputType>Library</OutputType>
+    <RootNamespace>GodotTools.ProjectEditor</RootNamespace>
+    <AssemblyName>GodotTools.ProjectEditor</AssemblyName>
+    <TargetFrameworkVersion>v4.5</TargetFrameworkVersion>
+    <BaseIntermediateOutputPath>obj</BaseIntermediateOutputPath>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>portable</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\Debug</OutputPath>
+    <DefineConstants>DEBUG;</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <ConsolePause>false</ConsolePause>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <Optimize>true</Optimize>
+    <OutputPath>bin\Release</OutputPath>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+    <ConsolePause>false</ConsolePause>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="System" />
+    <Reference Include="Microsoft.Build" />
+    <Reference Include="DotNet.Glob, Version=2.1.1.0, Culture=neutral, PublicKeyToken=b68cc888b4f632d1, processorArchitecture=MSIL">
+      <!--
+      When building Godot with 'mono_glue=no' SCons will build this project alone instead of the
+      entire solution. $(SolutionDir) is not defined in that case, so we need to workaround that.
+      We make SCons restore the NuGet packages in the project directory instead in this case.
+      -->
+      <HintPath Condition=" '$(SolutionDir)' != '' ">$(SolutionDir)\packages\DotNet.Glob.2.1.1\lib\net45\DotNet.Glob.dll</HintPath>
+      <HintPath>$(ProjectDir)\packages\DotNet.Glob.2.1.1\lib\net45\DotNet.Glob.dll</HintPath>
+      <HintPath>packages\DotNet.Glob.2.1.1\lib\net45\DotNet.Glob.dll</HintPath> <!-- Are you happy CI? -->
+    </Reference>
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="ApiAssembliesInfo.cs" />
+    <Compile Include="ApiSolutionGenerator.cs" />
+    <Compile Include="DotNetSolution.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="IdentifierUtils.cs" />
+    <Compile Include="ProjectExtensions.cs" />
+    <Compile Include="ProjectGenerator.cs" />
+    <Compile Include="ProjectUtils.cs" />
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="packages.config" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\GodotTools.Core\GodotTools.Core.csproj">
+      <Project>{639E48BD-44E5-4091-8EDD-22D36DC0768D}</Project>
+      <Name>GodotTools.Core</Name>
+    </ProjectReference>
+  </ItemGroup>
+  <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
+</Project>
diff --git a/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/IdentifierUtils.cs b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/IdentifierUtils.cs
new file mode 100644
index 0000000000..f93eb9a1fa
--- /dev/null
+++ b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/IdentifierUtils.cs
@@ -0,0 +1,197 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Text;
+
+namespace GodotTools.ProjectEditor
+{
+    public static class IdentifierUtils
+    {
+        public static string SanitizeQualifiedIdentifier(string qualifiedIdentifier, bool allowEmptyIdentifiers)
+        {
+            if (string.IsNullOrEmpty(qualifiedIdentifier))
+                throw new ArgumentException($"{nameof(qualifiedIdentifier)} cannot be empty", nameof(qualifiedIdentifier));
+
+            string[] identifiers = qualifiedIdentifier.Split('.');
+
+            for (int i = 0; i < identifiers.Length; i++)
+            {
+                identifiers[i] = SanitizeIdentifier(identifiers[i], allowEmpty: allowEmptyIdentifiers);
+            }
+
+            return string.Join(".", identifiers);
+        }
+
+        public static string SanitizeIdentifier(string identifier, bool allowEmpty)
+        {
+            if (string.IsNullOrEmpty(identifier))
+            {
+                if (allowEmpty)
+                    return "Empty"; // Default value for empty identifiers
+
+                throw new ArgumentException($"{nameof(identifier)} cannot be empty if {nameof(allowEmpty)} is false", nameof(identifier));
+            }
+
+            if (identifier.Length > 511)
+                identifier = identifier.Substring(0, 511);
+
+            var identifierBuilder = new StringBuilder();
+            int startIndex = 0;
+
+            if (identifier[0] == '@')
+            {
+                identifierBuilder.Append('@');
+                startIndex += 1;
+            }
+
+            for (int i = startIndex; i < identifier.Length; i++)
+            {
+                char @char = identifier[i];
+
+                switch (Char.GetUnicodeCategory(@char))
+                {
+                    case UnicodeCategory.UppercaseLetter:
+                    case UnicodeCategory.LowercaseLetter:
+                    case UnicodeCategory.TitlecaseLetter:
+                    case UnicodeCategory.ModifierLetter:
+                    case UnicodeCategory.LetterNumber:
+                    case UnicodeCategory.OtherLetter:
+                        identifierBuilder.Append(@char);
+                        break;
+                    case UnicodeCategory.NonSpacingMark:
+                    case UnicodeCategory.SpacingCombiningMark:
+                    case UnicodeCategory.ConnectorPunctuation:
+                    case UnicodeCategory.DecimalDigitNumber:
+                        // Identifiers may start with underscore
+                        if (identifierBuilder.Length > startIndex || @char == '_')
+                            identifierBuilder.Append(@char);
+                        break;
+                }
+            }
+
+            if (identifierBuilder.Length == startIndex)
+            {
+                // All characters were invalid so now it's empty. Fill it with something.
+                identifierBuilder.Append("Empty");
+            }
+
+            identifier = identifierBuilder.ToString();
+
+            if (identifier[0] != '@' && IsKeyword(identifier, anyDoubleUnderscore: true))
+                identifier = '@' + identifier;
+
+            return identifier;
+        }
+
+        static bool IsKeyword(string value, bool anyDoubleUnderscore)
+        {
+            // Identifiers that start with double underscore are meant to be used for reserved keywords.
+            // Only existing keywords are enforced, but it may be useful to forbid any identifier
+            // that begins with double underscore to prevent issues with future C# versions.
+            if (anyDoubleUnderscore)
+            {
+                if (value.Length > 2 && value[0] == '_' && value[1] == '_' && value[2] != '_')
+                    return true;
+            }
+            else
+            {
+                if (DoubleUnderscoreKeywords.Contains(value))
+                    return true;
+            }
+
+            return Keywords.Contains(value);
+        }
+
+        private static readonly HashSet<string> DoubleUnderscoreKeywords = new HashSet<string>
+        {
+            "__arglist",
+            "__makeref",
+            "__reftype",
+            "__refvalue",
+        };
+
+        private static readonly HashSet<string> Keywords = new HashSet<string>
+        {
+            "as",
+            "do",
+            "if",
+            "in",
+            "is",
+            "for",
+            "int",
+            "new",
+            "out",
+            "ref",
+            "try",
+            "base",
+            "bool",
+            "byte",
+            "case",
+            "char",
+            "else",
+            "enum",
+            "goto",
+            "lock",
+            "long",
+            "null",
+            "this",
+            "true",
+            "uint",
+            "void",
+            "break",
+            "catch",
+            "class",
+            "const",
+            "event",
+            "false",
+            "fixed",
+            "float",
+            "sbyte",
+            "short",
+            "throw",
+            "ulong",
+            "using",
+            "where",
+            "while",
+            "yield",
+            "double",
+            "extern",
+            "object",
+            "params",
+            "public",
+            "return",
+            "sealed",
+            "sizeof",
+            "static",
+            "string",
+            "struct",
+            "switch",
+            "typeof",
+            "unsafe",
+            "ushort",
+            "checked",
+            "decimal",
+            "default",
+            "finally",
+            "foreach",
+            "partial",
+            "private",
+            "virtual",
+            "abstract",
+            "continue",
+            "delegate",
+            "explicit",
+            "implicit",
+            "internal",
+            "operator",
+            "override",
+            "readonly",
+            "volatile",
+            "interface",
+            "namespace",
+            "protected",
+            "unchecked",
+            "stackalloc",
+        };
+    }
+}
diff --git a/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/ProjectExtensions.cs b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/ProjectExtensions.cs
new file mode 100644
index 0000000000..36961eb45e
--- /dev/null
+++ b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/ProjectExtensions.cs
@@ -0,0 +1,61 @@
+using GodotTools.Core;
+using System;
+using DotNet.Globbing;
+using Microsoft.Build.Construction;
+
+namespace GodotTools.ProjectEditor
+{
+    public static class ProjectExtensions
+    {
+        public static bool HasItem(this ProjectRootElement root, string itemType, string include)
+        {
+            GlobOptions globOptions = new GlobOptions();
+            globOptions.Evaluation.CaseInsensitive = false;
+
+            string normalizedInclude = include.NormalizePath();
+
+            foreach (var itemGroup in root.ItemGroups)
+            {
+                if (itemGroup.Condition.Length != 0)
+                    continue;
+
+                foreach (var item in itemGroup.Items)
+                {
+                    if (item.ItemType != itemType)
+                        continue;
+
+                    var glob = Glob.Parse(item.Include.NormalizePath(), globOptions);
+
+                    if (glob.IsMatch(normalizedInclude))
+                    {
+                        return true;
+                    }
+                }
+            }
+
+            return false;
+        }
+
+        public static bool AddItemChecked(this ProjectRootElement root, string itemType, string include)
+        {
+            if (!root.HasItem(itemType, include))
+            {
+                root.AddItem(itemType, include);
+                return true;
+            }
+
+            return false;
+        }
+
+        public static Guid GetGuid(this ProjectRootElement root)
+        {
+            foreach (var property in root.Properties)
+            {
+                if (property.Name == "ProjectGuid")
+                    return Guid.Parse(property.Value);
+            }
+
+            return Guid.Empty;
+        }
+    }
+}
diff --git a/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/ProjectGenerator.cs b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/ProjectGenerator.cs
new file mode 100644
index 0000000000..7cf58b6755
--- /dev/null
+++ b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/ProjectGenerator.cs
@@ -0,0 +1,227 @@
+using GodotTools.Core;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using Microsoft.Build.Construction;
+
+namespace GodotTools.ProjectEditor
+{
+    public static class ProjectGenerator
+    {
+        private const string CoreApiProjectName = "GodotSharp";
+        private const string EditorApiProjectName = "GodotSharpEditor";
+        private const string CoreApiProjectGuid = "{AEBF0036-DA76-4341-B651-A3F2856AB2FA}";
+        private const string EditorApiProjectGuid = "{8FBEC238-D944-4074-8548-B3B524305905}";
+
+        public static string GenCoreApiProject(string dir, IEnumerable<string> compileItems)
+        {
+            string path = Path.Combine(dir, CoreApiProjectName + ".csproj");
+
+            ProjectPropertyGroupElement mainGroup;
+            var root = CreateLibraryProject(CoreApiProjectName, out mainGroup);
+
+            mainGroup.AddProperty("DocumentationFile", Path.Combine("$(OutputPath)", "$(AssemblyName).xml"));
+            mainGroup.SetProperty("RootNamespace", "Godot");
+            mainGroup.SetProperty("ProjectGuid", CoreApiProjectGuid);
+            mainGroup.SetProperty("BaseIntermediateOutputPath", "obj");
+
+            GenAssemblyInfoFile(root, dir, CoreApiProjectName,
+                new[] {"[assembly: InternalsVisibleTo(\"" + EditorApiProjectName + "\")]"},
+                new[] {"System.Runtime.CompilerServices"});
+
+            foreach (var item in compileItems)
+            {
+                root.AddItem("Compile", item.RelativeToPath(dir).Replace("/", "\\"));
+            }
+
+            root.Save(path);
+
+            return CoreApiProjectGuid;
+        }
+
+        public static string GenEditorApiProject(string dir, string coreApiProjPath, IEnumerable<string> compileItems)
+        {
+            string path = Path.Combine(dir, EditorApiProjectName + ".csproj");
+
+            ProjectPropertyGroupElement mainGroup;
+            var root = CreateLibraryProject(EditorApiProjectName, out mainGroup);
+
+            mainGroup.AddProperty("DocumentationFile", Path.Combine("$(OutputPath)", "$(AssemblyName).xml"));
+            mainGroup.SetProperty("RootNamespace", "Godot");
+            mainGroup.SetProperty("ProjectGuid", EditorApiProjectGuid);
+            mainGroup.SetProperty("BaseIntermediateOutputPath", "obj");
+
+            GenAssemblyInfoFile(root, dir, EditorApiProjectName);
+
+            foreach (var item in compileItems)
+            {
+                root.AddItem("Compile", item.RelativeToPath(dir).Replace("/", "\\"));
+            }
+
+            var coreApiRef = root.AddItem("ProjectReference", coreApiProjPath.Replace("/", "\\"));
+            coreApiRef.AddMetadata("Private", "False");
+
+            root.Save(path);
+
+            return EditorApiProjectGuid;
+        }
+
+        public static string GenGameProject(string dir, string name, IEnumerable<string> compileItems)
+        {
+            string path = Path.Combine(dir, name + ".csproj");
+
+            ProjectPropertyGroupElement mainGroup;
+            var root = CreateLibraryProject(name, out mainGroup);
+
+            mainGroup.SetProperty("OutputPath", Path.Combine(".mono", "temp", "bin", "$(Configuration)"));
+            mainGroup.SetProperty("BaseIntermediateOutputPath", Path.Combine(".mono", "temp", "obj"));
+            mainGroup.SetProperty("IntermediateOutputPath", Path.Combine("$(BaseIntermediateOutputPath)", "$(Configuration)"));
+            mainGroup.SetProperty("ApiConfiguration", "Debug").Condition = " '$(Configuration)' != 'Release' ";
+            mainGroup.SetProperty("ApiConfiguration", "Release").Condition = " '$(Configuration)' == 'Release' ";
+
+            var toolsGroup = root.AddPropertyGroup();
+            toolsGroup.Condition = " '$(Configuration)|$(Platform)' == 'Tools|AnyCPU' ";
+            toolsGroup.AddProperty("DebugSymbols", "true");
+            toolsGroup.AddProperty("DebugType", "portable");
+            toolsGroup.AddProperty("Optimize", "false");
+            toolsGroup.AddProperty("DefineConstants", "$(GodotDefineConstants);GODOT;DEBUG;TOOLS;");
+            toolsGroup.AddProperty("ErrorReport", "prompt");
+            toolsGroup.AddProperty("WarningLevel", "4");
+            toolsGroup.AddProperty("ConsolePause", "false");
+
+            var coreApiRef = root.AddItem("Reference", CoreApiProjectName);
+            coreApiRef.AddMetadata("HintPath", Path.Combine("$(ProjectDir)", ".mono", "assemblies", "$(ApiConfiguration)", CoreApiProjectName + ".dll"));
+            coreApiRef.AddMetadata("HintPath", Path.Combine("$(ProjectDir)", ".mono", "assemblies", CoreApiProjectName + ".dll"));
+            coreApiRef.AddMetadata("Private", "False");
+
+            var editorApiRef = root.AddItem("Reference", EditorApiProjectName);
+            editorApiRef.Condition = " '$(Configuration)' == 'Tools' ";
+            editorApiRef.AddMetadata("HintPath", Path.Combine("$(ProjectDir)", ".mono", "assemblies", "$(ApiConfiguration)", EditorApiProjectName + ".dll"));
+            editorApiRef.AddMetadata("HintPath", Path.Combine("$(ProjectDir)", ".mono", "assemblies", EditorApiProjectName + ".dll"));
+            editorApiRef.AddMetadata("Private", "False");
+
+            GenAssemblyInfoFile(root, dir, name);
+
+            foreach (var item in compileItems)
+            {
+                root.AddItem("Compile", item.RelativeToPath(dir).Replace("/", "\\"));
+            }
+
+            root.Save(path);
+
+            return root.GetGuid().ToString().ToUpper();
+        }
+
+        public static void GenAssemblyInfoFile(ProjectRootElement root, string dir, string name, string[] assemblyLines = null, string[] usingDirectives = null)
+        {
+            string propertiesDir = Path.Combine(dir, "Properties");
+            if (!Directory.Exists(propertiesDir))
+                Directory.CreateDirectory(propertiesDir);
+
+            string usingDirectivesText = string.Empty;
+
+            if (usingDirectives != null)
+            {
+                foreach (var usingDirective in usingDirectives)
+                    usingDirectivesText += "\nusing " + usingDirective + ";";
+            }
+
+            string assemblyLinesText = string.Empty;
+
+            if (assemblyLines != null)
+                assemblyLinesText += string.Join("\n", assemblyLines) + "\n";
+
+            string content = string.Format(AssemblyInfoTemplate, usingDirectivesText, name, assemblyLinesText);
+
+            string assemblyInfoFile = Path.Combine(propertiesDir, "AssemblyInfo.cs");
+
+            File.WriteAllText(assemblyInfoFile, content);
+
+            root.AddItem("Compile", assemblyInfoFile.RelativeToPath(dir).Replace("/", "\\"));
+        }
+
+        public static ProjectRootElement CreateLibraryProject(string name, out ProjectPropertyGroupElement mainGroup)
+        {
+            if (string.IsNullOrEmpty(name))
+                throw new ArgumentException($"{nameof(name)} cannot be empty", nameof(name));
+
+            var root = ProjectRootElement.Create();
+            root.DefaultTargets = "Build";
+
+            mainGroup = root.AddPropertyGroup();
+            mainGroup.AddProperty("Configuration", "Debug").Condition = " '$(Configuration)' == '' ";
+            mainGroup.AddProperty("Platform", "AnyCPU").Condition = " '$(Platform)' == '' ";
+            mainGroup.AddProperty("ProjectGuid", "{" + Guid.NewGuid().ToString().ToUpper() + "}");
+            mainGroup.AddProperty("OutputType", "Library");
+            mainGroup.AddProperty("OutputPath", Path.Combine("bin", "$(Configuration)"));
+            mainGroup.AddProperty("RootNamespace", IdentifierUtils.SanitizeQualifiedIdentifier(name, allowEmptyIdentifiers: true));
+            mainGroup.AddProperty("AssemblyName", name);
+            mainGroup.AddProperty("TargetFrameworkVersion", "v4.5");
+
+            var debugGroup = root.AddPropertyGroup();
+            debugGroup.Condition = " '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ";
+            debugGroup.AddProperty("DebugSymbols", "true");
+            debugGroup.AddProperty("DebugType", "portable");
+            debugGroup.AddProperty("Optimize", "false");
+            debugGroup.AddProperty("DefineConstants", "$(GodotDefineConstants);GODOT;DEBUG;");
+            debugGroup.AddProperty("ErrorReport", "prompt");
+            debugGroup.AddProperty("WarningLevel", "4");
+            debugGroup.AddProperty("ConsolePause", "false");
+
+            var releaseGroup = root.AddPropertyGroup();
+            releaseGroup.Condition = " '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ";
+            releaseGroup.AddProperty("DebugType", "portable");
+            releaseGroup.AddProperty("Optimize", "true");
+            releaseGroup.AddProperty("DefineConstants", "$(GodotDefineConstants);GODOT;");
+            releaseGroup.AddProperty("ErrorReport", "prompt");
+            releaseGroup.AddProperty("WarningLevel", "4");
+            releaseGroup.AddProperty("ConsolePause", "false");
+
+            // References
+            var referenceGroup = root.AddItemGroup();
+            referenceGroup.AddItem("Reference", "System");
+
+            root.AddImport(Path.Combine("$(MSBuildBinPath)", "Microsoft.CSharp.targets").Replace("/", "\\"));
+
+            return root;
+        }
+
+        private static void AddItems(ProjectRootElement elem, string groupName, params string[] items)
+        {
+            var group = elem.AddItemGroup();
+
+            foreach (var item in items)
+            {
+                group.AddItem(groupName, item);
+            }
+        }
+
+        private const string AssemblyInfoTemplate =
+            @"using System.Reflection;{0}
+
+// Information about this assembly is defined by the following attributes.
+// Change them to the values specific to your project.
+
+[assembly: AssemblyTitle(""{1}"")]
+[assembly: AssemblyDescription("""")]
+[assembly: AssemblyConfiguration("""")]
+[assembly: AssemblyCompany("""")]
+[assembly: AssemblyProduct("""")]
+[assembly: AssemblyCopyright("""")]
+[assembly: AssemblyTrademark("""")]
+[assembly: AssemblyCulture("""")]
+
+// The assembly version has the format ""{{Major}}.{{Minor}}.{{Build}}.{{Revision}}"".
+// The form ""{{Major}}.{{Minor}}.*"" will automatically update the build and revision,
+// and ""{{Major}}.{{Minor}}.{{Build}}.*"" will update just the revision.
+
+[assembly: AssemblyVersion(""1.0.*"")]
+
+// The following attributes are used to specify the signing key for the assembly,
+// if desired. See the Mono documentation for more information about signing.
+
+//[assembly: AssemblyDelaySign(false)]
+//[assembly: AssemblyKeyFile("""")]
+{2}";
+    }
+}
diff --git a/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/ProjectUtils.cs b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/ProjectUtils.cs
new file mode 100644
index 0000000000..22cf89695d
--- /dev/null
+++ b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/ProjectUtils.cs
@@ -0,0 +1,72 @@
+using GodotTools.Core;
+using System.Collections.Generic;
+using System.IO;
+using DotNet.Globbing;
+using Microsoft.Build.Construction;
+
+namespace GodotTools.ProjectEditor
+{
+    public static class ProjectUtils
+    {
+        public static void AddItemToProjectChecked(string projectPath, string itemType, string include)
+        {
+            var dir = Directory.GetParent(projectPath).FullName;
+            var root = ProjectRootElement.Open(projectPath);
+            var normalizedInclude = include.RelativeToPath(dir).Replace("/", "\\");
+
+            if (root.AddItemChecked(itemType, normalizedInclude))
+                root.Save();
+        }
+
+        private static string[] GetAllFilesRecursive(string rootDirectory, string mask)
+        {
+            string[] files = Directory.GetFiles(rootDirectory, mask, SearchOption.AllDirectories);
+
+            // We want relative paths
+            for (int i = 0; i < files.Length; i++) {
+                files[i] = files[i].RelativeToPath(rootDirectory);
+            }
+
+            return files;
+        }
+
+        public static string[] GetIncludeFiles(string projectPath, string itemType)
+        {
+            var result = new List<string>();
+            var existingFiles = GetAllFilesRecursive(Path.GetDirectoryName(projectPath), "*.cs");
+
+            GlobOptions globOptions = new GlobOptions();
+            globOptions.Evaluation.CaseInsensitive = false;
+
+            var root = ProjectRootElement.Open(projectPath);
+
+            foreach (var itemGroup in root.ItemGroups)
+            {
+                if (itemGroup.Condition.Length != 0)
+                    continue;
+
+                foreach (var item in itemGroup.Items)
+                {
+                    if (item.ItemType != itemType)
+                        continue;
+
+                    string normalizedInclude = item.Include.NormalizePath();
+
+                    var glob = Glob.Parse(normalizedInclude, globOptions);
+
+                    // TODO Check somehow if path has no blob to avoid the following loop...
+
+                    foreach (var existingFile in existingFiles)
+                    {
+                        if (glob.IsMatch(existingFile))
+                        {
+                            result.Add(existingFile);
+                        }
+                    }
+                }
+            }
+
+            return result.ToArray();
+        }
+    }
+}
diff --git a/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/Properties/AssemblyInfo.cs b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/Properties/AssemblyInfo.cs
new file mode 100644
index 0000000000..09333850fc
--- /dev/null
+++ b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/Properties/AssemblyInfo.cs
@@ -0,0 +1,27 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+
+// Information about this assembly is defined by the following attributes.
+// Change them to the values specific to your project.
+
+[assembly: AssemblyTitle("GodotTools.ProjectEditor")]
+[assembly: AssemblyDescription("")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("")]
+[assembly: AssemblyProduct("")]
+[assembly: AssemblyCopyright("Godot Engine contributors")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+// The assembly version has the format "{Major}.{Minor}.{Build}.{Revision}".
+// The form "{Major}.{Minor}.*" will automatically update the build and revision,
+// and "{Major}.{Minor}.{Build}.*" will update just the revision.
+
+[assembly: AssemblyVersion("1.0.*")]
+
+// The following attributes are used to specify the signing key for the assembly,
+// if desired. See the Mono documentation for more information about signing.
+
+//[assembly: AssemblyDelaySign(false)]
+//[assembly: AssemblyKeyFile("")]
+
diff --git a/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/packages.config b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/packages.config
new file mode 100644
index 0000000000..13915000e4
--- /dev/null
+++ b/modules/mono/editor/GodotTools/GodotTools.ProjectEditor/packages.config
@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<packages>
+  <package id="DotNet.Glob" version="2.1.1" targetFramework="net45" />
+</packages>
\ No newline at end of file